According to the studies by the inventors of the present invention, for example, the following technologies are known in non-contact electronic devices such as an IC card, an IC tag, an RFID, and a mobile phone.
A non-contact electronic device comprising semiconductor integrated circuits having functions of CPU and memory in its interior has been spreading in the field of transportation and finance. Though not particularly limited, the non-contact electronic device does not have a power supply such as a battery, and it operates by generating power from electromagnetic waves received by an antenna. The non-contact electronic device receives data sent from an interrogator (inquiry device) by modulating the electromagnetic waves, and then performs a signal processing of the received data by the CPU and the memory. As a result, according to the obtained data, the load between antenna terminals is fluctuated to modulate the electromagnetic waves received by the antenna, and the data is sent to the interrogator.
For the non-contact electronic device described above, there exists a circuit technology in which a highly efficient and stable power supply voltage is generated by combining a rectifier function and a regulator function, thereby achieving the extension of a communication distance (for example, see Japanese Patent Application Laid-Open Publication No. 2001-274339 (Patent Document 1)).
Further, for the achievement of a wider range of communications, there exists a technology in which the power supply circuit disclosed in Patent Document 1 is used so as to protect withstand voltage of the elements constituting the power supply circuit (for example, see Japanese Patent Application Laid-Open Publication No. 2003-319574 (Patent Document 2)).